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Print 33 comment(s) - last by Keeir.. on Jan 10 at 12:47 AM

CFRP will also make the BMW i3 more lightweight with extra space

BMW said the i3 will have lower repair and insurance costs thanks to the use of carbon fiber reinforced plastic (CFRP). 
 
According to a new report from Autoblog Green, the BMW i3's use of CFRP will make repairs easier because most bumps at a traffic light or a parking lot will only damage exterior plastic parts, which are easily replaced. But for bigger collisions that actually do affect the carbon fiber, the damage stays local to that one spot. 
 
"When we evaluated carbon fiber, we started doing the safety, crash and repair concepts right from the beginning because just deciding on carbon fiber and then, when we're done, looking at [the details] would be a huge risk," said Manuel Sattig, communications manager for BMW i.
 
"Carbon fiber is, of course, a new material. Our dealers need to be trained for that specific repair system. But, if you look at the i3, if the car has a small bit of damage, someone hits you at a traffic light or bumps into you in a parking garage, you don't hit carbon fiber, you mostly damage the exterior plastic parts. They can very easily be replaced because you click out the damaged part and replace it with a new one. If you have a stronger accident, then, of course, carbon fiber will be damaged. The interesting thing is that carbon fiber is not deforming, so the damage only happens locally and it breaks only at that specific area."


Sattig noted that BMW has already talked the U.S. National Highway Traffic Safety Administration (NHTSA) and the insurance industry about the use of the new material, and they've decided to go with a "very low" insurance system. 

CFRP will also make the BMW i3 more lightweight with extra space. 

BMW officially announced the all-electric i3 back in July, giving the new vehicle a price tag of $41,350 USD. 

The i3 will feature a 22-kilowatt, 450-pound lithium ion battery, which will provide power to a rear-mounted electric motor. The i3 packs 170 horsepower and 184 pound-feet of torque, allowing the single-gear i3 to accelerate from 0-30 miles per hour in 3.5 seconds and 0-60 mph in about 7.0 seconds. Its top speed is limited to 93 MPH. 
 
For those concerned about range, the i3 has an electric range of 80-100 miles, and the battery can be charged with a standard system in about three hours.

In October, it was reported that BMW may boost production of the i3 EV due to early demand. At that time, the automaker said customers reserved over 8,000 i3s ahead of the official launch in Europe. 
 
BMW has plans to sell 10,000 i3 units next year and previously announced that it would adjust build capacity according to market demand.

The i3 will go on sale in the U.S. during the second quarter of 2014.

Source: Autoblog Green



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RE: Deforming
By theapparition on 12/14/2013 2:39:58 AM , Rating: 1
Sigh, you use a lot of textbook replies but obviously no experience.

Example 1, you still refer to CFRP in structural loading talking about deflection. CFRP is just plastic, so either you mispoke, or still lack the fundamental understanding. CFRP is NO different than what's being used on modern car body panels. CFRP is NOT Carbon Fiber. True carbon fiber panels get strenth from strand weave.

Example 2. Saying CF is just taped together by epoxy matrix anyway. The fibers are what gives carbon fiber its strength, and severing them would lead to a repaired part with the same strength as just epoxy matrix.

Example 3. I said quite explicitly that I kept the discussion simple. You went out of your way to get detailed, but still lack some of the basic fundamentals from experience. You think the average body shop will have the capabilities to repair? Yes, composite engineering is complex, and the dailytech readership only needs the cliffs. While the filament weave helps, the matrix still takes most compression loading.

So I ask you this. Have you ever done any design with composites?


RE: Deforming
By Keeir on 1/10/2014 12:47:07 AM , Rating: 2
Your suffering from some misconceptions. http://www.youtube.com/watch?v=gt1k3BLN7pw&list=PL...

With the i3, BMW is using CFRP from the entire body frame. They are using continuous fiber tape/sheets for many of the parts currently. Since multiple layers are required, they are using a epoxy type resin. BMW is not using "flake" filled molded parts for body structure . Sure for the body panels, and even some structural components, but a substantial portion of the underlying frame is composed of oriented plys.

In this situation, it is entirely possible to repair them. These type of structures have been used in aviation for years with repairs. It takes less than 3 days to be trained on the process. Its very simple. Maybe not quite as simple as welding steel, but still relatively simple. Taper sand damage. Lay in some adhesive epoxy sheet. Lay in some sheets/tape with some more epoxy. Cover with vacuum bag. Heat. Simple.

quote:
While the filament weave helps, the matrix still takes most compression loading.


Hmmm. So, how do you explain a nearly 20 fold increase in compression strength from a typical un-reinforced epoxy matrix to one filled with multi-orientated plys/tape runs? Yes, your right, in the flake filled situation, your stability will be limited by matrix. In an oriented sheet lay-up, the epoxy is not a matrix so much as a shear transfer/binding agent.

quote:
So I ask you this. Have you ever done any design with composites?


I'll ask you something in return. How many oriented ply layup panels have you had repaired and tested to failure? I've done several. You can completely repair oriented ply carbon fiber reinforced plastic composites. Simply scarf them. http://www.crc-acs.com.au/index.php/contact-us/12-...


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